France is boosting security at Jewish religious sites after blanks were fired at a synagogue west of Paris amid renewed concerns about anti-Semitism around the country.

French President Francois Hollande met Sunday with leaders of the country's Jewish community and pledged to fight extremism and anti-Semitism "with the greatest firmness."

He said that authorities "in the coming days, in the coming hours" will increase security at Jewish religious sites so they won't be subject to the kind of attack that targeted a synagogue in the Paris suburb of Argenteuil on Saturday night.

A synagogue representative said witnesses heard what sounded like a weapon being fired and that police said blanks had been fired and empty bullet casings found. Local police would not comment on the incident to the AP. Services were canceled at the synagogue, the representative said, speaking on condition of anonymity because a police investigation is under way.

It came hours after police carried out raids across France on Saturday targeting a suspected jihadist cell of young Frenchmen recently converted to Islam. DNA on a grenade that exploded last month at a kosher grocery store led them to a member of the cell, who was killed in a shootout with police Saturday.